arXiv subjects
Publications and source records attributed to Alan Kostelecky.
A brief summary is given of recent developments concerning a Lorentz-violating extension of the standard model and its implications for experiments testing Lorentz and CPT symmetry.
This talk discusses the sensitivity of electron-positron and proton-antiproton Penning-trap experiments to CPT- and Lorentz-violating effects in the context of an extension of the minimal standard model and quantum electrodynamics.
In this talk, a brief summary is given of the possibility of using neutral-kaon oscillations to bound CPT- and Lorentz-breaking parameters in an extension of the minimal standard model.
Apparent violations of CPT and Lorentz symmetry might arise in nature as a result of spontaneous symmetry breaking in a theory beyond the standard model. This talk summarizes a few relevant theoretical and experimental issues, with some emphasis on implications for CPT tests with neutral-B mesons.
The sensitivity of experiments with neutral mesons to possible indirect CPT violation is examined. It is shown that experiments conventionally regarded as equivalent can have CPT reaches differing by orders of magnitude within the framework of a minimal CPT- and Lorentz-violating extension of the standard model.
Minuscule violations of CPT and Lorentz invariance might arise in an extension of the standard model as suppressed effects from a more fundamental theory. In this contribution to the CarruthersFest, I present and answer some questions about CPT and the possibility of its violation.
A theoretical analysis is performed of Penning-trap experiments testing CPT and Lorentz symmetry through measurements of anomalous magnetic moments and charge-to-mass ratios. Possible CPT and Lorentz violations arising from spontaneous symmetry breaking at a fundamental level are treated in the context of a general extension of the SU(3) x SU(2) x U(1) standard model and its restriction to quantum electrodynamics. We describe signals that might appear in principle, introduce suitable figures of merit, and estimate CPT and Lorentz bounds attainable in present and future Penning-trap experiments. Experiments measuring anomaly frequencies are found to provide the sharpest tests of CPT symmetry. Bounds are attainable of approximately $10^{-20}$ in the electron-positron case and of $10^{-23}$ for a suggested experiment with protons and antiprotons. Searches for diurnal frequency variations in these experiments could also limit certain types of Lorentz violation to the level of $10^{-18}$ in the electron-positron system and others at the level of $10^{-21}$ in the proton-antiproton system. In contrast, measurements comparing cyclotron frequencies are sensitive within the present theoretical framework to different kinds of Lorentz violation that preserve CPT. Constraints could be obtained on one figure of merit in the electron-positron system at the level of $10^{-16}$, on another in the proton-antiproton system at $10^{-24}$, and on a third at $10^{-25}$ using comparisons of $H^-$ ions with antiprotons.
In the context of conventional quantum field theory, we present a general Lorentz-violating extension of the minimal SU(3) x SU(2) x U(1) standard model including CPT-even and CPT-odd terms. It can be viewed as the low-energy limit of a physically relevant fundamental theory with Lorentz-covariant dynamics in which spontaneous Lorentz violation occurs. The extension has gauge invariance, energy-momentum conservation, and covariance under observer rotations and boosts, while covariance under particle rotations and boosts is broken. The quantized theory is hermitian and power-counting renormalizable, and other desirable features such as microcausality, positivity of the energy, and the usual anomaly cancellation are expected. Spontaneous symmetry breaking to the electromagnetic U(1) is maintained, although the Higgs expectation is shifted by a small amount relative to its usual value and the $Z^0$ field acquires a small expectation. A general Lorentz-breaking extension of quantum electrodynamics is extracted from the theory, and some experimental tests are considered. In particular, we study modifications to photon behavior. One possible effect is vacuum birefringence, which could be bounded from cosmological observations by experiments using existing techniques. Radiative corrections to the photon propagator are examined. They are compatible with spontaneous Lorentz and CPT violation in the fermion sector at levels suggested by Planck-scale physics and accessible to other terrestrial laboratory experiments.
We discuss the application of quantum-mechanical supersymmetry to particle traps. The supersymmetric-partner wave functions may be used to describe a valence fermion in a trap system with an isotropic harmonic-oscillator potential. Interactions with the core are incorporated analytically. The close similarity of this approach to the application of supersymmetry in atomic systems is made explicit by means of a radial mapping between the two systems.
We examine the revival structure of Rydberg wave packets. These wave packets exhibit initial classical periodic motion followed by a sequence of collapse, fractional/full revivals, and fractional/full superrevivals. The effects of quantum defects on wave packets in alkali-metal atoms and a squeezed-state description of the initial wave packets are also described. We then examine the revival structure of Rydberg wave packets in the presence of an external electric field, i.e., the revival structure of Stark wave packets. These wave packets have energies that depend on two quantum numbers and exhibit new types of interference behavior.
We present a generic treatment of wave-packet revivals for quantum-mechanical systems. This treatment permits a classification of certain ideal revival types. For example, wave packets for a particle in a one-dimensional box are shown to exhibit perfect revivals. We also examine the revival structure of wave packets for quantum systems with energies that depend on two quantum numbers. Wave packets in these systems exhibit quantum beats in the initial motion as well as new types of long-term revivals. As an example, we consider the revival structure of a particle in a two-dimensional box.
In this talk, I review the possibility that CPT and Lorentz symmetry might be spontaneously broken in nature by effects originating in a theory beyond the standard model, and I discuss some existing and future experimental tests.
For isotropic confining Ioffe-Pritchard or TOP potentials, a valence fermion trapped with a closed core of other fermions can be described by an analytical effective one-particle model with a physical eigenspectrum. Related constructions exist for Paul and Penning traps. The analytical models arise from quantum-mechanical supersymmetry.
A theoretical framework is introduced that describes possible CPT-violating effects in the context of quantum electrodynamics. Experiments comparing the anomalous magnetic moments of the electron and the positron can place tight limits on CPT violation. The conventional figure of merit adopted in these experiments, involving the difference between the corresponding $g$ factors, is shown to provide a misleading measure of the precision of CPT limits. We introduce an alternative figure of merit, comparable to one commonly used in CPT tests with neutral mesons. To measure it, a straightforward extension of current experimental procedures is proposed. With current technology, a CPT bound better than about one part in $10^{20}$ is attainable.
This talk provides a short overview of recent results on possible CPT violation and some associated experimental signatures.
Spontaneous CPT breaking arising in string theory has been suggested as a possible observable experimental signature in neutral-meson systems. We provide a theoretical framework for the treatment of low-energy effects of spontaneous CPT violation and the attendant partial Lorentz breaking. The analysis is within the context of conventional relativistic quantum mechanics and quantum field theory in four dimensions. We use the framework to develop a CPT-violating extension to the minimal standard model that could serve as a basis for establishing quantitative CPT bounds.
The revival structure of wave packets is examined for quantum systems having energies that depend on two nondegenerate quantum numbers. For such systems, the evolution of the wave packet is controlled by two classical periods and three revival times. These wave packets exhibit quantum beats in the initial motion as well as new types of long-term revivals. The issue of whether fractional revivals can form is addressed. We present an analytical proof showing that at certain times equal to rational fractions of the revival times the wave packet can reform as a sum of subsidiary waves and that both conventional and new types of fractional revivals can occur.
Parameters describing CPT violation are extracted from a variety of rate asymmetries in the neutral-$D$ system. The precision to which these parameters could be measured in present and planned machines is examined.